New machine to benefit Chena River

FAIRBANKS (AP) -- Instead of being dumped back into the Chena River, minerals removed at the water treatment plant will be disposed of at the landfill thanks to a new $860,000 machine.

The Golden Heart Utilities plant had used lime to remove several naturally-occurring minerals such as calcium, iron and manganese. Those minerals, as well as the lime, were dumped back into the river after being removed for drinking water.

The machine, called a dewatering press, forms the minerals into solids for disposal at landfills.

''It's state-of-the-art,'' said Golden Heart Utilities spokesman David Dean. ''Over the long run, the quality of the water in the Chena will be enhanced.''

The Alaska Department of Environmental Conservation had been granting the utility permits to dump the minerals back into the river. The quantities involved weren't considered a health hazard.

Before the press began operation, between 1.5 and 1.8 million pounds of water and solids were pumped into the Chena River each year.

The two-story press shoots water through a series of 70 screens, which serve to filter the mineral content in the water. The result is a slurry with the consistency of wet clay.

''It's real sloppy, gooey stuff,'' Dean said.

The slurry, which is roughly 70 percent solid and 30 percent water, is removed from the press in the form of thick cakes. Since the press began operating in early December, it has been producing about 35,000 pounds of cake material a week, with the amount likely to increase during the summer when more water is used.

The material is deposited in a container and taken to the landfill, where Dean said it eventually dries into a powdery substance.

The water put into the press that doesn't end up in the slurry is piped out, emerging clean enough to be recycled into drinking water.